Peromyscus
maniculatusbairdii
has a shorter tail, ears, skull, and hind foot than P. m.
gracilisis It is grayish to reddish brown with white underparts.
The fur is short, soft, and dense. The finely-haired tail is
bicolored, the darker top half and the lighter bottom sharply
differentiated.

They are primarily a nocturnal species. Peromyscus
maniculatusbairdii
spends most of its time on the ground but it is also an adept
climber. Activity centers around a nest and food cache. In terrestrial
prairie subspecies, a nest is constructed just below ground
level in its own burrow or one abandoned by another animal.
Forest dwelling subspecies construct nests near the ground in
stumps, logs, brush piles, tree cavities, reconstructed bird
nests, tree bark, or even cottages or outbuildings. Nests are
made of rounded masses of vegetable matter (as much as 100 mm
in diameter).

It
is omnivorous. It eats a wide variety of plant and animal matter
depending on what is available, including insects and other
invertebrates, seeds, fruits, flowers, nuts, and other plant
products.

At
birth, the Peromyscus
maniculatusbairdii
has a mass of about 1.5 g. The young are born hairless with
wrinkled, pink skin, closed eyes, and folded over ear pinnae.
Juvenile hair begins to develop on the second day after birth.
On the third day, the pinnae unfold with the ear canal opening
on the tenth day. Eyes open on the fifteenth day, and the young
are weaned between day 25 and 35. Conception can occur as early
as 35 days, but the first estrus typically occurs around 49
days.

Peromyscus
maniculatus bairdii
are found in forested areas in the Panhandle of Alaska and across
N Canada, south through most of continental USA, excluding the
SE and E seaboard, to southernmost Baja California and to Sur
NC Oaxaca, Mexico; including many landbridge islands. In
Michigan,Peromyscus
maniculatus bairdii is found in open areas (preferably plowed
or cultivated fields, early stages of grasslands, or along lake
shores) of the Lower Peninsula and the southwestern Upper Peninsula.(see
details: Mammal Species of the World, Vol 2, 2005, p1071-2).